The present invention relates to dampers for use in connection with washing machines.
Dampers for washing machines typically are enclosed cylindrical members with a spring-loaded piston coupled to a rod extending from the cylindrical body and attached between the cabinet of the washing machine and the drum for the clothing being washed. Typically, the piston includes a damping material and lubrication to provide a frictional interface between the piston and the inner wall of the cylindrical housing. U.S. Pat. No. 7,549,519 discloses an improved version of such a damper in which some movement of the washer drum is allowed before damping occurs. Other examples of dampers employed in a washing machine environment include U.S. Pat. No. 7,445,098, U.S. Publication No. 2003/0183994, and PCT Application No. PCT/IB2015/051190.
One issue with closed cylinder type dampers is that, during extended heavy duty use, the interface between the internal piston of the damper and the inner cylindrical wall of the housing generates a considerable amount of heat and, during an extended period of use, may wear out or reduce the effectiveness of the damper. U.S. Pat. No. 8,640,837 represents a different form of damper in which the non-cylindrical housing is provided with a guide track and a slide containing a friction pad to engage opposite walls of the housing. There remains a need, however, for an improved linear-type damper which has mounting capabilities for positioning in existing washing machine designs, namely, one with a hemispherical cap and extending piston rod, such that it can be coupled to current washing machine designs. It would also be desirable to provide a reliable, long life damper which can largely be molded of a polymeric material with a minimum number of components.